Oh, how I love a tartan fabric! Must be my anglo-saxon heritage, hee. At any rate, being a long-time sewist I've worked with and worn my fair share of it.
So, I think I know why saramir and kellygirl are liking the side view in #4. Let me get technical. It's because this view shows none of the most prominent horizontal stripe - the lightest one - close to the hem. See how there are three dominant lighter stripes running horizontally? Light colours come forward or stand out while darker ones recede. That's why we say darker colours are more slimming.
The cut of this skirt is already at least A-line. With your dark top tucked in this is making you look even more pear-shaped to my eye. (I agree with lyn 67 for sure on that - you'll get more slimming effect if your dark top just covers that first dominant stripe that falls right at your hips.) So IMHO I would hem your skirt above that third dominant blue stripe. Actually, because the black stripe just above it seems to be secondary I'd hem it just at the bottom of the burgundy background colour, not because of where it actually falls on you, but because that's how you'll get more of the background colour giving you a leaner look. (This may be enough of a change w/o taking it in at the sides as saramir suggests.) See how in #3 there's a bit of the blue peeking out at the bottom? That's why the side view looks better - none showing there.
It looks like the skirt has been well cut to hang straight ,so if you just follow the stripe around the bottom you shouldn't have any problem with uneven hem line. And by using the widest burgundy stripe at the bottom you can eliminate any potential problem of having to make minor adjustment in length to keep it even as you go around. Although, seeing only peeks of the back from the side views, it's hard to say.
Oh, tartan, how beautiful but tricky you are!
